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IT34488: MQ listener runqmqlsr not accepting new connections and also consuming high CPU

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APAR status

  • Closed as program error.

Error description

  • After unexpected termination (e.g. process killed by  user or
    the process ended
    unexpectedly) of an amqrmppa process, MQ listener process
    runmqlsr not accepting new
    connections and also consumes high CPU.
    
    The MQ listener runmqlsr trace had repeated failures with errno
    111 from connect  socket API.
    
     15:55:31.460322    34925.1           :       ----{
    xcsSetSocketAddress
     15:55:31.460324    34925.1           :        sun_path:
    /var/mqm/sockets/TEST/@qmpersist/spipe/host1/ccc.23506
     15:55:31.460326    34925.1           :       ----}
    xcsSetSocketAddress rc=OK FunctionTime=4
     15:55:31.460328    34925.1           :       ----{  socket
     15:55:31.460332    34925.1           :       ----}! socket
    rc=Unknown(8) FunctionTime=4
     15:55:31.460334    34925.1           :       ----{  connect
     15:55:31.460339    34925.1           :       ----}! connect
    rc=Unknown(FFFFFFFF) FunctionTime=5
     15:55:31.460342    34925.1           :            connect()
    failed errno = 111
    

Local fix

  • Restart the MQ listener
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users using MQ channels
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    A defect in MQ listener in handling unexpected termination of an
    amqrmppa process
    could cause the process to go into an infinite loop and resulted
    in high CPU usage. The issue occurred when the process ID of the
    failed process was re-assigned to a new process before the MQ
    listener detected the failure, and so was only likely to be
    observed in environments with limited availability of new PIDs.
    

Problem conclusion

  • MQ listener code has been modified to prevent the process going
    into infinite loop when an amqrmppa process terminates and its
    PID is reassigned.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.12
    v9.1 LTS   9.1.0.8
    v9.2 LTS   9.2.0.2
    v9.x CD    9.2.3
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT34488

  • Reported component name

    IBM MQ BASE M/P

  • Reported component ID

    5724H7261

  • Reported release

    900

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-10-09

  • Closed date

    2021-03-23

  • Last modified date

    2021-03-23

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    IBM MQ BASE M/P

  • Fixed component ID

    5724H7261

Applicable component levels

[{"Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.0"}]

Document Information

Modified date:
24 March 2021